diff --git a/internal/wire/ok.go b/internal/wire/ok.go
index e76b591..f416341 100644
--- a/internal/wire/ok.go
+++ b/internal/wire/ok.go
@@ -4,8 +4,6 @@ type OK struct{}
 
 func (OK) NetTag() string { return "ok" }
 
-func (OK) MarshalJSON() ([]byte, error) { return []byte(`"ok"`), nil }
-
 func init() {
 	Register(func() Value { return new(OK) })
 }